Thermostat



Nov. 19, 1940. BENNETT 2,221,752

THERMOSTAT Fil ed June 5, 1938 Patented Nov. 19; 1940 UNITED STATES PATENT OFFICE 2,221,152

g mmosm'r Dale L. Bennett, Oak rark,-lll., assignmto Inter- Harveste national New Jersey Companma corporation of This invention relates to a cooling system and more particularly to a means interposed in the 1 outlet conduit of the system for controlling the passage of cooling medium therethrough, the 5 means further embodying means for releasing pressure within the system.

Cooling systems for internal combustionengines comprise generally a radiator and a water jacket about the block and cylinder head of the engine, the jacket and the radiator beingconnected by an inlet and an outlet conduit. Ordinarily, a thermostat or some heat responsive means is located in the outlet conduit. This means prevents or limits circulation of the cooling medium in the system until a predetermined temperature is reached, after which the means opens to permit complete circulation. When the system is cold, or at least below the temperature required to open the thermostat, it is substantially sealed against the escape of pressure. When it is desired to add cooling medium to the system through the conventional filler in the radiator, it is found'that suiilcient cooling medium to completely fill the system cannot be put in until the temperature has increased suflicicntly the closed thermostat, and the incoming cooling medium, when the system is cold, cannot displace. the amount of air within the system. Thus, it is necessary to operate the engine until the temperature increases, after which the necessary additional cooling medium may be added.' Howtype thermostat.

Another object. is to provide this means in the form of a heat responsive element which will permit release of the pressure within the system through the outlet conduit at or below thetemperature at which the-thermostat closes.

And still another object is to dispose this means in a manner resisting passage of water through the air pressure opening or leak so that ever, this procedure involves considerable loss of instances is readily adapted to any conventional interference will not be had withthe warming up of the system.

A comprehensive understanding of the objects and desirable features of the invention may be had from the following detailed description of one preferred form of the invention as illustrated inthe accompanying sheet of drawings,

wherein- Figure 1 is a diagrammatic sectional view of that portion of a cooling system necessary to the illustration and description of the invention;

Figure 2 is an enlarged detail sectional view of the heat responsive means embodying the invention. I

The cooling system illustrated in Figure 1 is more or less conventional, and parts unnecessary to an understanding-of the invention have been omitted. The system comprises generally a radiator l0 and the water jacket portion of an internal combustion engine H. is provided with a lower water tank [2, which is connected to the water jacket of the engine H by an inlet l3. The radiator is provided at its top with an upper water tank or header It, to open the thermostat. This condition is theresult of the substantial sealing of the system by thermostat in the present instance comprises a casing 20 formed with an annular flange; 2|,

- which. when located in position, fits between a" flange on the conduit l1 and the'upper surface of the head-portion I8. The casing 20 is provided with an opening 22, which is adapted to be closed by a heat responsive means 23, which includes a valve 24 of the poppet type, which is operative to open and close the opening 22. This valve may be generally referred to as a thermostatic valve and is controlled by a conventional type of heat responsive element, as at 25. Means in the form of a ball or strip member 26 is rigidly secured to the casing, as at 2'|,and'supports the thermostatic valve means.

The radiator Ill The description of the thermostat so far approximates that of most conventional devices 0:,

this type and is disposed in the cooling system in the usual manner and for the usual purpose.

- These are well understood by those skilled in the art, and only a generaldescription of the operation of the thermostat in conjunction with the system will be necessary. when the temperature The thermostat illustrated and'described in conjunction with the present invention also embodies means for providing a restricted opening or leak for permitting the release of pressure within the system, as previously mentioned. This means is inthe form of a heat responsive element 28, or second thermostatic valve, and comprises a bi-metallic element secured to the underside of the valve 24, as at 29. This element cooperates with a'small opening 30 formed in the valve 24. The two metal strips comprising this element are arranged in a manner permitting closure of the opening 30 at a temperature lower than the temperature at which the valve 24 closes. This second valve or element, however, remains entirely open below a predetermined temperature, preferably at about 100 F. The properties of the strips comprising the element are such that the element preferably closes the opening 30 before the opening of the valve 24, so that proper warming up of the cooling medium may be effected.

When the cooling system is cold,,that is, below the predetermined temperature 01' 100 F., the parts of the thermostat are in the positions shown in Figure '2; that is, the valve 24 closes the opening 22 and the second valve or element 28' opens the opening 80. With the system thus cold, an adequate supply of cooling medium may be added thereto, the air within the system being displaced by the added cooling medium and passing throughthe opening 30. Thus, this pressure, that so adversely affected previous systerms, is released'by the provision of the second thermostatic valve or heat responsive element 28.

In warming up the system, the element 28 remains open until-a predetermined temperature, as

100 F., is reached, ai'terwhich it closes and circulation of the cooling medium is prevented throughout the system until the predetermined temperature is reached, at which the valve 2| begins to open. In the present invention. the element 28 remains closed while the temperature of the system is above 160 F., although it is immaterial whether or not it, is permitted to open. However, because of the. arrangement-oi the two strips comprising the element, as previously mentioned', the opening 30 will remain closed above 100 F., or whatever temperature is chosen as desirable.

From the foregoing description, it will be readily seen that an improved cooling system has 5 been provided as embodying one preferred form oi the present invention. It will be appreciated however, that the thermostatic device, or heatresponsive means, is .readily usable in cooling systems of various types, and it will be further understood that numerous modifications and alterations may be made in the construction and operation of the device without departing from the spirit and scope of the invention as defined in the appended claims.

What is claimed is! 1. A thermostat for a cooling system comprising a casing having an outlet, 8. heat responsive means including a valve adapted to open and close the outlet at predetermined higher and lower temperatures, said valve having an opening therein, and second valve means for opening and closing said opening, said means comprising a heat responsive metallic strip carried at one end by the first valve and responsive to opensaid. opening at a predetermined temperature lower than either of the aforesaid temperatures to permit venting of the system during filling of the system while the first valve is closed, said strip beingresponsive to close said opening at a -9 I higher temperature to prevent circulation until the first valve opens. I

2. A temperature regulator for the cooling system. 01' an internal combustion engine, comprising means providing a generally circular valve port, a generally circular valve associated with said port, said valve having a smaller port 011- set radially from its center, heat responsive means for openings and closing the valve at predetermined higher and lower temperatures and including a connection to the valve at a point spaced radially from the smaller opening, and a second heat responsive means associated .with

. said smaller opening and comprising a bimetallic strip carried at one end by the valve and extending across said opening, said strip being responsive to open said opening at a predetermined temperature lower than either of the aforesaid temperatures to permit venting of the system during filling or the system while the first valve is closed, said strip being responsive to close said opening at a higher temperature to prevent circulation until the first valve opens.

DALE L. BENNETT. 

